The present invention relates to a light-emitting diode and a manufacturing method therefor, and more particularly to an edge-emitting light-emitting diode for outputting light from its end facet and a manufacturing method therefor.
In a light-emitting diode, when facet reflection occurs in its optical waveguide, the stimulated emission of light caused by the facet reflection makes the emission of stable natural light difficult. For this reason, it has been proposed to form an active layer serving as the light-emitting portion at one end of the facet radiation type light-emitting diode and also form a light-absorbing portion made of an active layer aligned with the active layer serving as the light-emitting portion(Japanese Publication No. 7-97661).
According to the light-emitting diode including the light-absorbing portion, out of all the light emitted from the light-emitting portion, the light traveling through the light-emitting diode to the light-absorbing portion is absorbed by the light-absorbing portion with the result that the facet reflection of the light can be prevented, making it possible to suppress the stimulated emission of light.
In the conventional light-emitting diode, however, between the active layer serving as the light-emitting portion and the active layer serving as the light-absorbing portion, there is the intervening InP block layer having a refractive index different from that of the InGaAsP active layer.
Accordingly, the light is refracted at the interface between the active layer and the block layer, and consequently all the light going from the light-emitting portion to the light-absorbing portion cannot be securely guided to the light-absorbing portion. For this reason, conventionally, a refracted portion of the light is likely to cause stimulated emission by facet reflection, and the emission characteristics are liable to deteriorate during operation at low temperature.